Research On Electric-Vehicle Charging Station Based On High-frequency Soft-switching Intelligent Charging Technology

The technology of EV(Electric vehicle)charging station design, fast and efficientcharging technology and the technology of EV battery management system has becamethe development bottleneck of EV industry. Therefore our thesis is focus on EVcharging station based on high-frequency soft-switching Intelligent chargingtechnology for in-depth study.Firstly, we introduce the structure of control and the management system of EVcharging station and the basic configuration of EV charging station, propose andelaborate on the three network structure of EV charging station, compare and analysisof the phase-controlled rectifier technology and high-frequency switching rectifiertechnology. high frequency switching rectifier technology—whose hardware is ofsmall size，light weight and efficient power conversion—is our technology roadmap.Compare and analysis of the characteristics and conventional charging methods ofthree kinds of conventionally-powered battery, determine the intelligent controlscheme combining of constant current，constant voltage and trickle as our prototypescheme, using MSP430F149 microcontroller as the control chip. We introduce the fullbridge converter topology and operating principle, compare and analysis of three kindsof full-bridge converter control, determine phase-shifting full-bridge control grategy asour prototype control grategy, forming phase-shifting pulse by UCC3895-chip.High-frequency soft-switch including zero-voltage soft switch (zvs) andzero-voltage zero-current soft-switch(zvzcs), we exhaustively discuss the conventionalphase-shifting full-bridge zvs topology, zvs conditions, working principle and workingprocess, derivate the interrelated formula, analysis and discuss the zvs load range andduty loss in depth. After extensive literature analysis, we summary many kinds ofvariative topologys of the conventional phase-shifting full-bridge zvzcs DC/DCconversion topology based on the analysis of zvs topology(the primary side with theauxiliary circuit or the secondary side with the auxiliary circuit). Through synthesisoptimization, we propose the topology of the secondary side with active clampauxiliary circuit and the primary side with blocking capacitors based on engineeringexperience.Finally, we detailedly discuss about the topology structure, working principle andworking process of phase-shifting full-bridge zvzcs DC/DC conversion with the passive clamp auxiliary circuit on the secondary side, accurately derivate and calculatecircuit parameters. Combining with the previous analysis for zvs, we compare andanalysis its soft-switching conditions, achieve range and duty loss, and determine thetopology of the secondary side with active clamp auxiliary circuit and the primary sidewith blocking capacitors as the theory of the prototype in this article. This topologyconversion circuit has a wide load range, the small duty loss, flexible output controland high precision, high efficiency power conversion.Finally, according to the technical standards of the State Grid Corporation ofChina, we design the overall structure of the prototype, electrical systems, the maincircuit of power transmission, the hardware and software design of control circuit bythe modular design concept. Prototype experiment and test waveforms and data showthat the phase-shifting full-bridge zvzcs power transformation theory applied to EVcharger is correct and feasible, design scheme and procedures is a reasonable choice.